Dark Side
by Micksterz
Summary: Kiera is an old friend of some agents with a past. She lives away from most people, trying to keep a low profile. She's a psychic, but that isn't her only secret. She has another side, too; a dark side. But when an unknown enemy strikes against the Earth and abducts an enemy, Natasha goes to Kiera as an Avengers representative for help, will Kiera learn to deal with her dark side?
1. Chapter 1

**This is my next Avengers fanfics -(Go ahead, call me obsessed. I don't care.)- and it also has an OC character. This fanfics isn't in first person, but in third. Okay, warning(s): possibly minor coarse language as the story progresses, possible character death (Who knows where this fanfics will go), mentions and flashbacks of torture (You'll understand when the story gets there. But you may have speculations now), and whatever else happens in this story. Sorry, most things aren't entirely set in stone.**

**Okay, DISCALIMER: I do NOT own the Avengers. If I did, trust me, the movie would've ended much differently.  
**

A woman was sitting on her porch, a book in her hands. It was obvious on her face that she was completely engrossed in the book. It was also obvious by the book's spine that it had been read and used many times before. In the light, tinted green by the hundreds of leaves that whistled in the slight breeze, the woman's pale skin looked somewhat shadowed. Her eyes, which were still very much intent on the book before her, were shining in the light. A brilliant gold color, Kiera had always had people note on her striking gold eyes. She wore black skinny jeans on the brisk, November afternoon, and didn't seem to mind the rather sharp wind. She also wore a short sleeve shirt that was colored a deep red, resembling the color of blood.

While this woman seemed entirely typical, she was far from it. As she reread her favorite book, the woman knew she held a secret in her heart that none would ever guess. That is, if it weren't for the few files that may have been left over. The woman brushed a strand of straight fawn-colored hair from her face just before her head snapped up, scanning the area. It was as if she heard something, as if she was a sensitive deer that heard a hunter. But she didn't run. Instead, the woman elegantly stood and set down the book with an uncanny grace. She walked down the steps and stopped a few feet from her porch, smiling.

"Well, well, well, my friend," she called. "Long time no see, hmm?" she asked with a chuckle. A mirth of laughter was heard as another woman stepped forward, out of the shade of the forest. This woman also had red hair, but with a more fiery color. Her eyes were steel-gray, and she moved with a sort of deadly lithe.

"It's been too long, Kiera," the woman answered. "But, I'm sad to say I'm here for business and not to catch up."

"Natasha, you know I'll do mostly anything, if I can actually help. What is it? Do you need another medic aboard the Helicarrier? Another lone shooter? Negotiator? Forensic scientist? Or just someone to placate Fury?" the woman, Kiera, asked in reply.

"All of those, that's for sure, but none of those are why I'm here. We need you on our team. As an Avenger," Natasha answered. "We could use someone with your abilities, you know." Kiera tensed, seeming just about to reply when Natasha cut her off quickly. "And the team, including Fury and the rest of SHIELD, only knows that you are a psychic. They know nothing about the, er, other part," Natasha finished. Kiera watched Natasha stiffly.

"Natasha, you and I both know that I can't join. You know the reason. You found out why I can't work with or for anyone on a team like that all those years ago, back in Moscow. Nothing's changed since then. I can't, Natasha. It- I, could hurt too many people," Kiera replied, some kind of heaviness weighing her voice down.

"That was almost ten years ago, Kiera. We were only children. You-" Natasha started, but Kiera cut her off.

"I'm just the same as then. I may have only been a child, but you're still who you were then, aren't you? Still a skilled assassin, still sometimes feel the effects of the brainwash? Natasha, I'm the same as I was. Still that same thing. That thing to be feared and hated," Kiera said, spitting the last sentence out like poison.

"Kiera, you have to stop blaming yourself for that. And, frankly, those people deserved what happened. They-" but Natasha didn't get to finish that thought; Kiera cut her off again.

"No one deserves that, Natasha! No one! No matter what they did or how bad they truly were, no one deserves that!" Kiera exclaimed. Natasha stared at her, as Kiera fell silent. Then Kiera laughed darkly. "I may have lied. There is one person who deserves that. But that person is the only one who isn't affected by it." Kiera let out another dark laugh, leaving Natasha looking shocked.

"Kiera-"

"Oh, don't you go '_Kiera_'-ing me, Natasha. You know that what I say is true," Kiera said, her voice low. "And I know it, too."

Natasha let out a frustrated sigh. She shook her head before taking a deep breath. "Kiera. We need you on this. The world could be lost if you don't help us."

"You handled Loki perfectly well last time the world was in danger, and he's a god. I think you can take on anything with your little group," Kiera interrupted. "Why do you need my help?"

"Because Loki's missing. He's not in his Asgardian cell anymore; all that's left is a few hundred blood splatters. Thor was horrified to know that the guards abused his brother how they did. But there are obvious fingerprints, hair fibers and blood samples all around the cell. We could use a forensic scientist for that. We need to find Loki," Natasha explained.

"I can be a forensic scientist, easy. But why does it sound like there's more?"

"Because there is. After we find Loki, or after he finds us, we need a medic to care for whatever wounds he might have. And you're the best option, since you're the closest thing we have to a supernatural medic, so-"

"But, can't the medics on Asgard care for Loki?" Kiera asked, cutting Natasha off again.

"Part of Loki's punishment was that any and every Asgardian, except for the guards, are unable to come into any contact with Loki, to teach him-"

"What it meant to truly be alone in the world," Kiera finished. "That's horrible." Kiera shuddered at the thought of the mental torture alone Loki may have had to go through.

"In short, yeah."

"So what does it have to do with the… other side?" Kiera asked. "Why do you need any more than a psychic, forensic scientist, medic?"

"Because of two things. One; we're expecting to have to fight whatever took Loki eventually. We barely overpowered the god, all five of us, and this thing just plucked him out of thin air-"

"Which was while he was in chains and with a muzzle preventing him from speaking or using any magic. You had to deal with full-powered Loki," Kiera pointed out.

"And then, the second reason. The Avengers are falling apart, Kiera," Natasha said. "You're the only person I can think if that could stitch a sorry bunch like us back together again."

Kiera couldn't help but smile slightly. "At least your trust in me hasn't dwindled. And I'm sure that you haven't stated any of these concerns or even let slip that you're worried?"

"Of course not. Most of the Avengers have yet to see the side if me that you know," Natasha said with a smile. "You know I'm not one to be open. It took you months to get me to say a word to you that wasn't required."

Kiera laughed. "True, very true. But look what my perseverance got me; a friend that isn't fuzzy or furry all over."

"Still keeping odd creatures around the house, Kiera?" Natasha asked with a smile, her tone a teasing, admonishing tone.

"Well, of course. What else? You want to meet them? Three Newfoundlands: Vic; he's five years old, Reverse; she's three years old, and Andy; he's seven months old. One Greyhound- you remember Skillet, right? She's eight now. Two German shepherd puppies- only about ten weeks old. Brother and sister; Gun and Horizon. Then there's-"

"How many dogs do you have, Kiera?" Natasha asked in disbelief. "Do you have an entire shelter of them?"

"No! I only have seven!" Kiera protested. "The last one is Link, and she's Andy's age. She's a Sheltie." Just as the last words slid from Kiera's lips, she turned and whistled. A pack of seven dogs came running. They ran to Kiera and Natasha. Kiera clicked her tongue, and the dogs almost immediately fell into a sort of line, sitting. Kiera smiled, before beginning to point to the dogs. "Skillet," she said, pointing to a light blue-silver Gray Hound. "Vic," she continued down the line, pointing to a tall, lean, and muscular brown Newfoundland. Even under all of his thick, dark fur that Vic had, it was obvious that he was very agile. "Reverse," she stated as she gestured to a black Newfoundland. She wasn't as tall as Vic, nor as fuzzy, but shorter and with smoother fur. "Andy," Kiera continued, pointing to a light brown and white patched Newfoundland. "Link," she addressed a small white and black dog with floppy, short-ish ears that half pointed up. "Gun and Horizon," she said finally, the two puppies looking up at Natasha and Kiera. Their ears flopped slightly, and they looked practically the same. Horizon just had a bright flash of white across her face, against the typical dark brown of German shepherds.

"And that's all of them!" Kiera said brightly. "All seven!" Natasha just shook her head, hiding a smile.

"I can't imagine how you care for all of them. Or how you can stand all of them," Natasha said, shaking her head.

"Well, a cat person wouldn't understand. I just love my dogs."

Natasha chuckled. "I can tell. Now, how did you get them to all sit in a line? It's as if you taught them to fall-in, or something."

"I just clicked my tongue. It took forever to teach them, but they got the concept. After a lot of training, but it paid off," Kiera explained. Then, she smiled deviously, and clicked her tongue again. That must have been the 'fallout' command, because the dogs broke formation, and Reverse, Andy, Link, Gun, and Horizon all jumped up at Natasha. Skillet and Vic were nosing at Natasha. And, somehow, the seven dogs got Natasha down. Kiera laughed as Natasha was covered in wet, slobbery doggy kisses.

"Hey- help!" Natasha shouted as Andy laid himself on Natasha's stomach, and licked her face. Kiera laughed harder, almost doubling over. Soon, though, she clicked her tongue. The dogs hopped off, and 'fell-in'.

"That was," Natasha started, picking herself up off the ground, "unexpected," she finished as she dusted herself off.

"That was," Kiera started, mocking Natasha. "Freaking hilarious," she finished with a laugh, grinning from ear to ear.

"Oh, shut up."

"Hey, is that how you treat your new teammate? I thought you wanted me on the team," Kiera teased. Natasha blinked at Kiera.

"You're joining?" Natasha asked hesitantly, disbelieving. As if she didn't expect Kiera to give in that easily.

"I guess so," Kiera said after a pause. "But, on one condition: my dogs get to come with me anywhere I go." Natasha rolled her eyes, but nodded.

"Sure thing. Fury might pop a vein when he finds seven dogs on his Helicarrier and Stark will hate the fact that seven dogs will be living in his tower, but they can deal with it."

"Great," Kiera said. "Then I'm in."


	2. Chapter 2

Kiera brushed another piece of hair from her face. Her gold eyes twinkled curiously as she regarded the Helicarrier. _What if this isn't a good idea?_ Kiera asked herself. She had all she needed slung over her shoulder in a black backpack, and held the leashes attached to all of her dogs in the other hand. Kiera's curious gaze turned suspicious when Fury came out with a group of males.

Two males were blonds, both muscular and tall. One had longer hair than the other and wore clothing that looked like armor and held a hammer. The other wore a costume that reminded Kiera of the American flag. But both blonds had blue eyes. Then, there were two males who had brown hair and brown eyes. One was noticeably shorter than everyone else, and this rather amused Kiera, despite the fact that she was still shorter. The other had glasses on and didn't have a goatee like the other male. Then there was the last male who had blue-gray eyes and blond-brown hair. He stood with the group, but seemed a bit separate. Recognition passed in Kiera's gold eyes and she smiled slightly. Then Fury cleared his throat.

"Agent Kiera. Long time no see," Fury said. Kiera looked lazily over to Fury, before smirking.

"Right back at ya, Eyepatch," she replied. "Guess I'm back in business, huh?" She laughed sharply. "Can't say I didn't see this coming, though."

"Right," Fury nodded. Then, he seemed to notice the dogs. "Hasn't been any lost love between you and animals now, has there?"

"Did you expect there to have been?" Kiera asked with a laugh, but also with a challenge underneath. Fury simply half-smiled and gave Kiera a curt nod.

"Then I'll leave the team to get you up to speed and settled in. I don't have to warn you about some being more of womanizers than others, right?" Fury asked, finishing with a slight glare to the shortest male. She gave Fury a smile, as if something was funny.

"Aw, you actually do care, Eyepatch. Don't worry about me, though. I can take care of myself," Kiera said with a sly smirk. Then she faced the team, and proceeded to come up with their nicknames. She approached them one-by-one, smiling.

"I am Thor Odinson, Maiden Kiera," the blond male with long hair said in a booming voice that sounded alike to thunder, taking her hand and kissing it. Kiera raised an eyebrow. "It is a pleasure to meet you."

"Yeah, you too, Thundershock," Kiera said with a nod. She moved on to the other blond.

"Hello, ma'am. I'm Steve Rogers, also known as Captain America," the male said. Kiera nodded.

"Hey, Spangles," Kiera replied. She noticed that the short male looked amused, and Kiera could tell that Natasha was, too.

Kiera moved onto the short male. Now that she was closer, she could see a blue glow coming through the male's Black Sabbath shirt. He winked at her with a smirk.

"Tony Stark, Iron Man, genius, billionaire, playboy, philanthropist," the male introduced.

"Yeah, okay, Pretty Boy," Kiera said, already sure what kind of guy this Tony was.

"Pretty boy? You think I'm pretty?" Tony asked with a smirk, with a challenge.

"No need to inflate your ego any more than it already is, Pretty Boy," was Kiera's reply. Then she was in front of the other brunette male, and she could feel the radiation coming off of him.

"Doctor Bruce Banner," he said. Kiera nodded.

"Hello, Dr. Gamma," she said. Everyone froze and stared at Kiera- except for Natasha. She cracked up.

"Told you guys she was something, right?"

"Yeah, but I don't entirely believe she can placate a furious Fury," Tony said.

"Oh, trust me. I've got that part covered, Pretty Boy. No need to worry your narcissistic little brain of yours about it." Kiera's words only gained more laughter from Natasha. Kiera moved onto the final male.

"Agent Barton," Kiera greeted with a smile. "So nice to finally see you again, huh?" Barton's mask of indifference disappeared and Kiera and Barton embraced like old friends.

"Wait- You know Legolas?" Tony asked, dumbfounded.

"'Course I know Clint. Nat, Clint and I used to be on a team."

"I thought you would've forgotten," Clint said, chuckling. Natasha rolled her eyes at Clint. "What?"

"Yes, I totally would've forgotten Budapest," Kiera said sarcastically.

"True," Clint said, trailing off. His eyes went to the ground, and Kiera smiled, teasingly swatting his shoulder.

"C'mon, Arrowhead. You get to show me around the Helicarrier with Nat. After all, I did disappear off the map for, what? Fifteen years? Twenty?"

"Seventeen."

"You kept track?" Kiera asked, blinking at Clint. He only shrugged.

"Wait, wait, wait a second. Let me get this straight. You know Legolas? And you two were on a team with Romanoff in Budapest?" Tony asked, dumbfounded. Kiera turned to Tony.

"Yes, Pretty Boy. You said you were a genius. This isn't that hard to follow. Clint, Natasha and I were on a team. We were in lots of places, and yes, Budapest was one of them. Do you understand?" Kiera explained very slowly, as if Tony was a child that was having issues with learning. Tony grumbled something and Kiera only smirked, before dropping the leashes that held her dogs. They immediately went after Tony, ramming into him. The dogs managed to get Tony down, and Andy sat on his chest, licking his face. Natasha and Clint hid their amused smiles, Bruce watched with a slightly snort, Steve was staring at the dogs and then Kiera and then the dogs again, his gaze shifting back and forth. Thor was laughing, his laughter booming throughout the area. "Oh, I'm sorry, Pretty Boy," Kiera said, feigning to be apologetic. "My dogs can get a bit carried away at times."

"Get them off of me," Tony demanded, as the dogs squirmed around and on top of him. Kiera smiled at Tony, a look of fake ignorance on her face.

"What was that, Pretty Boy? I don't think I caught that."

"Get them off of me!"

"What?"

"GET YOUR DAMN MUTTS OFF OF ME!" Tony yelled. Kiera stared down at Tony, as if judging him. She narrowed her eyes, before clicking her tongue. All seven dogs climbed off of Tony and sat in a line behind Kiera.

"Are you okay, now, princess? Were the dogs too much for you to handle? I hope they didn't soil your clothes," Kiera said, contempt in her voice. Whatever test Kiera had just given Tony, it seemed as if he failed. Natasha walked to Kiera and put a hand on her shoulder silently. Kiera took a breath and nodded, before facing Tony again. "Bye-bye, Pretty Boy," she said cheerfully, before walking back over to Clint with Natasha, her dogs following her at her heels.

* * *

Soon, the Avengers and Kiera were on the Helicarrier. They were all in the main board room, files and tablets and test results spread everywhere. Steve and Thor sat together, away from the clutter of information that they didn't really understand. Clint and Natasha sat near Kiera, who was reading something, pacing back and forth. Her dogs sat in a close corner, watching Kiera. Fury was leaning against the wall, watching what seemed to be the entire room, even with only one eye. Tony sat in a chair across the table from Natasha and Clint, spinning in the chair. Bruce was beside Tony, staring at the files on the table.

"Kiera, if you don't stop pacing, you're going to wear a hole though my floor," Fury finally said. Kiera stopped and turned to Fury, staring at him for a moment, before returning to the file she was reading. She resumed her pacing as if nothing had happened.

"Was it only Loki's blood in that cell? Did you test all of it? Searched for any other evidence that another presence was in there with him?" Kiera asked, acting more like a detective than just a forensic scientist. She had been a detective's partner for most of her life after disappearing off of SHIELD's radar, so she knew how to handle things like this. But Kiera had never handled a godly case before. Or a kidnapping. She dealt more with murders than anything. "Were there any other bodily fluids in that cell? Saliva?" Kiera bit her lip before continuing. "Maybe even semen? I'm not sure what kind of torture Loki was put through, but rape could have certainly been part of it." Thor stiffened at the prospect.

"I had not checked, Maiden Kiera," Thor answered, his voice unnervingly level.

"Well, that's alright. I can go there myself and collect the evidence. If that's okay, that is," Kiera said. She knew that she had to tread lightly for now. Sometimes in cases she had to deal with the families of the victims, and things could get touchy.

"If it helps us find my brother, then I am okay with it," Thor said. Kiera nodded, before returning to the file.

"Loki has magic, right?" Kiera suddenly asked after a dozen silent minutes.

"Yes, he does possess the gift of magic," Thor answered.

"Does he have a certain type of magic that's specific to him, or something? A magic signature?" Kiera asked. "It could just be something we might be able to follow, if we could track it."

"His magic is unique to himself, yes," Thor answered. Kiera smiled.

"Then I think we've found a way to track him, then. Thundershock, I'm gonna need to go to Asgard. Pretty Boy, I want any file you can find on Loki's magic and the Chitauri. Dr. Ga-"

"Why the Chitauri?" Tony cut in, challenging Kiera. Kiera gave him an annoyed look.

"He was in charge of a Chitauri army, right?" Kiera asked.

"Yeah," Tony answered slowly, as if trying to see where this was going.

"Well, the army had to be someone's before it was his. An army like that couldn't have just been conjured up in that little time. Someone had to be holding it for him, holding it _before _him. The Chitauri are a lead," Kiera explained. "Do you understand, Pretty Boy?" she asked.

"Yeah," he answered, before working on his tablet, digging around for files.

"Good. Now, Dr. Gamma, do you know if there are any leftover DNA samples of the Chitauri? I know every DNA sample is different, except for twins and all, but they all have around the same traits. If I can get a hold of a few-"

"You can find the similarities in the species and track the Chitauri that way," Tony cut in again. "Smart."

"Thanks, Pretty Boy, but I don't need your approval," Kiera said, before turning back to Bruce. "Can you get me any?"

"I think so," he replied. Kiera nodded.

"Alright, Arrowhead, Loki was in your head, right?" she asked, her voice not as strict as before.

"Yeah," Clint replied, sounding as if he didn't want to be reminded.

"Did you ever pick up on fears, or worries, or threats that Loki was given? By someone other than the Avengers and SHIELD?"

"Not that I can remember. I didn't ask questions. I didn't need to," Clint explained.

"Well, that's alright. There wasn't much I could've used there, anyway, Arrowhead. I need you more for your perception skills than anything else, anyway," Kiera said, trying to lift the mood. "Okay, Spangles?" she said, he voice back to stern and focused.

"Yes, ma'am?" Steve answered, standing up at attention. Kiera rolled her eyes.

"At ease, soldier," she said. There were a few snickers around the room as Steve slowly stood down, seeming a bit embarrassed. "Spangles, I'm not a captain. There's no point in treating me like one. I'm also not a lady. No point in acting like I am." Steve gave Kiera a strange look, but Kiera didn't seem to mind. "I just need to know about the Tesseract. Hydra had it when you were first alive, right?"

"Yes, ma'a- Yes," Steve replied.

"How did he find out about it? Where did he get it from?" Kiera inquired.

"From legend; he heard about it, about how it held the power of the gods," Steve said. "Where he got it from, I wouldn't know. Sorry."

"Alright. Hey, Thundershock, what do you know about the Tesseract?" Kiera asked.

"It used to belong to the Frost Giants, until Odin took it from them after the war," Thor began, but Kiera cut him off there.

"So it was originally a Frost Giant treasure? Would they try to take Loki from you to get back at taking the Tesseract from them?" Kiera pressed.

"The Frost Giants didn't want Loki when he was a child-" Thor tried, but Kiera cut him off.

"But now he's a mischievous god with the power of magic and who can wield the Tesseract. They could've wanted him. Or maybe they wanted him as revenge for killing his father. He did do that, right? Murdered Laufey, even though he was his son?" Kiera asked, cutting in again. Thor nodded.

"Aye, he did."

"There's another lead. The Frost Giants may have wanted vengeance. Both the Frost Giants and the Chitauri are brutal races, right?" Kiera asked no one in particular this time.

"Aye," Thor answered. "Bloodthirsty, battle hungry, and brutal."

"Is that their nature or how they're raised, Thundershock?" Kiera inquired.

"Raised. Loki was nothing like that-"

"Until he ended up with the Chitauri and plotting a war against Earth, with a plan to rule us," Kiera cut in, cutting Thor off. "But, either way, bloodthirsty and beastly. Sounds like they'd enjoy torturing Loki," Kiera said, finishing in a solemn tone. Silence fell over the Avengers, until Fury finally cleared his throat.

"Well, then lets get to work, finding our abducted criminal, people," he ordered.


End file.
